function popup(url, br, ho) {
   var breite=400; var hoehe=300;
   if (br > 0) { breite = br; }
   if (ho > 0) { hoehe = ho; }
   PopupWin = window.open(url, "PopUpWindow", ",width="+breite+",height="+hoehe+",top=100,left=100,scrollbars=yes,status=no");
   return false;
}